Technical Field
Embodiments of the present invention generally relates to an electrophotographic image forming apparatus such as a copier, a facsimile machine, a printer, or a multifunction peripheral (MFP, i.e., a multifunction machine) having at least two of copying, printing, facsimile transmission, plotting, and scanning capabilities.
Description of the Related Art
Image forming apparatuses such as copiers and printers generally include a transfer roller to press against an image bearer, and a contact therebetween is called “transfer nip” (i.e., a transfer position). It is possible that toner transferred from the image bearer adheres to the transfer roller. Then, when a recording medium such as a paper sheet is nipped in the transfer nip, it is possible that a back side or an edge face of the recording medium is soiled with toner transferred from the transfer roller. To prevent such soil of toner of the sheet, for example, a cleaning bias different from a transfer bias is applied to the transfer roller in intervals between sheets transported to the transfer nip between the transfer roller and the image bearer.